From b6c0d63082e73299088fce71a83d807d7c6c3fd8 Mon Sep 17 00:00:00 2001
From: yanglsh <yanglsh@shanghaitech.edu.cn>
Date: Sun, 13 Jul 2025 21:53:34 +0800
Subject: [PATCH] fix: `if_then_some_else_none` FP when require type coercion

---
 clippy_lints/src/if_then_some_else_none.rs |  4 +++-
 tests/ui/if_then_some_else_none.fixed      | 16 ++++++++++++++++
 tests/ui/if_then_some_else_none.rs         | 16 ++++++++++++++++
 3 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/clippy_lints/src/if_then_some_else_none.rs b/clippy_lints/src/if_then_some_else_none.rs
index 9e94280fc074..7d76c4d4a3c7 100644
--- a/clippy_lints/src/if_then_some_else_none.rs
+++ b/clippy_lints/src/if_then_some_else_none.rs
@@ -5,7 +5,8 @@ use clippy_utils::msrvs::{self, Msrv};
 use clippy_utils::source::snippet_with_context;
 use clippy_utils::sugg::Sugg;
 use clippy_utils::{
-    contains_return, higher, is_else_clause, is_in_const_context, is_res_lang_ctor, path_res, peel_blocks,
+    contains_return, expr_requires_coercion, higher, is_else_clause, is_in_const_context, is_res_lang_ctor, path_res,
+    peel_blocks,
 };
 use rustc_errors::Applicability;
 use rustc_hir::LangItem::{OptionNone, OptionSome};
@@ -79,6 +80,7 @@ impl<'tcx> LateLintPass<'tcx> for IfThenSomeElseNone {
             && !expr.span.in_external_macro(cx.sess().source_map())
             && self.msrv.meets(cx, msrvs::BOOL_THEN)
             && !contains_return(then_block.stmts)
+            && !expr_requires_coercion(cx, then_expr)
         {
             let method_name = if switch_to_eager_eval(cx, expr) && self.msrv.meets(cx, msrvs::BOOL_THEN_SOME) {
                 "then_some"
diff --git a/tests/ui/if_then_some_else_none.fixed b/tests/ui/if_then_some_else_none.fixed
index f774608712d1..0458923d24e9 100644
--- a/tests/ui/if_then_some_else_none.fixed
+++ b/tests/ui/if_then_some_else_none.fixed
@@ -122,3 +122,19 @@ const fn issue12103(x: u32) -> Option<u32> {
     // Should not issue an error in `const` context
     if x > 42 { Some(150) } else { None }
 }
+
+mod issue15257 {
+    #[derive(Default)]
+    pub struct Foo {}
+    pub trait Bar {}
+    impl Bar for Foo {}
+
+    #[allow(clippy::manual_is_multiple_of)]
+    fn maybe_get_bar(i: u32) -> Option<Box<dyn Bar>> {
+        if i % 2 == 0 {
+            Some(Box::new(Foo::default()))
+        } else {
+            None
+        }
+    }
+}
diff --git a/tests/ui/if_then_some_else_none.rs b/tests/ui/if_then_some_else_none.rs
index 8b8ff0a6ea00..5bef83838b81 100644
--- a/tests/ui/if_then_some_else_none.rs
+++ b/tests/ui/if_then_some_else_none.rs
@@ -143,3 +143,19 @@ const fn issue12103(x: u32) -> Option<u32> {
     // Should not issue an error in `const` context
     if x > 42 { Some(150) } else { None }
 }
+
+mod issue15257 {
+    #[derive(Default)]
+    pub struct Foo {}
+    pub trait Bar {}
+    impl Bar for Foo {}
+
+    #[allow(clippy::manual_is_multiple_of)]
+    fn maybe_get_bar(i: u32) -> Option<Box<dyn Bar>> {
+        if i % 2 == 0 {
+            Some(Box::new(Foo::default()))
+        } else {
+            None
+        }
+    }
+}